Oil shale retorting method and apparatus



Dec. .8, 1970 Rw. wHn'l-:ACRE 3RD 3,545,092

OIL SHALE RETORTlNG METHOD AND APPARATUS k2 sheets-sheet 2 Filed June` 4.'. 196e INVENTOK Raaf/zr n'. wH/rEAcRE/Zl United States Patent O 3,546,092 OIL SHALE RETORTING METHOD AND APPARATUS Robert W. Whiteacre 3rd, Verona, Pa., assignor to Koppers Company, Inc., a corporation of Delaware Filed June 4, 1968, Ser. No. 734,398 Int. Cl. C10g 1/00 U.S. Cl. 208-11 10 Claims ABSTRACT F THE DISCLOSURE The improved method for retorting shale oil particles includes the additional steps of comminuting shale oil narticles that have been retorted in a iirst stage and are hot; passing a gaseous fluid through the comminuted particles; removing the product gases and oil; separating the product gases and oil from ore fines; flowing the product gases and oils into a products collecting conduit or burning the product gases at a fuel ldistributor in the first stage retorting process.

BACKGROUND OF THE INVENTION This invention relates to an improved method and apparatus for retorting oil shale ore to obtain oil and gas. Heretofore, retorting of oil shale has been carried out in a vertical kiln or retort wherein the oil shale ore, which is in the form of crushed and screened particles, is fed into the top of the kiln. The oil shale ore is preheated in the upper zone of the kiln by the heat of counterflowing gases moving upwardly from a lower combustion zone.

Below the preheating zone, the oil shale ore particles are heated to retorting temperature by either hot combustion gas, produced by internal or external combustion of recycled gas, or by hot recycle gas which has been indirectly heated external of the kiln. Retorting of the oil shale ore drives off the kerogen products which are withdrawn from near the top of the kiln. The spent oil shale residue heats a counterflow of recycle gas as the residue descends to the bottom of the kiln from where it is continually removed.

It has long been recognized that the oil shale ore, after being retorted in accordance with the prior art, contains a large proportion of its original energy that has not been removed. Such residual energy is present in the oil shale are in the form of organic matter.

In a copending application Ser. No. 564,994, filed July 13, 1966, now abandoned, and assigned to the assignee of this invention, it was disclosed that the spent shale ore particles have an organic rich core surrounded by a shell which is depleted of kerogen. Based on this depletion disclosure, the smaller particles have very little, or essentially no central core of organic material, since the depth or thickness of the shell approaches, or is equal to, the radius of the particle. The larger particles, however, having a larger core, are richest in the residual organic material.

Heretofore, the kerogen in the central core has not been entirely removed by processes known in the art. But, the process of the present invention recovers practically all of the kerogen heretofore remaining in the central core of the shale oil particles. The additional kerogen recovered in accordance with the method of the present invention may be as much as of the kerogen recovered by carrying into practice methods known in the prior art.

SUMMARY OF THE INVENTION The invention comprises treating shale oil ore particles that have been retorted in a first stage to recover residual energy, by comminuting said particles while hot; collecting the comminuted particles in a receptacle; flowing a gaseous iluid through said comminuted particles; and removing the residual energy in the form of product gas and oil from the receptacle. Thereafter, the product gas and oil ilow through a separator to remove ore fines, and the product gas and oil may be conducted into a product removal conduit, or burned at a fuel distributor in order to retort the ore particles in the first stage.

For a further understanding of the invention and for advantages and features thereof, reference may be made to the following description taken in conjunction with the drawings which show, for the purpose of exemplication, a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a schematic arrangement of apparatus available in the prior art for retorting shale oil ore;

FIG. 2 is a schematic arrangement of a first apparatus in accordance with the invention, and that is suitable for carrying into practice the method of the invention;

FIG. 3 is a schematic arrangement of a second apparatus in accordance with the invention, and that is suitable for carrying into practice the method of the invention; and

FIG. 4 is a schematic arrangement of a third apparatus in accordance with the invention, and that is suitable for carrying into practice the method of the invention.

DETAILED DESCRIPTION FIG. 1 illustrates in schematic form apparatus 11, of a type known in the prior art, for retorting oil shale ore. Such apparatus includes: a vertical retorting furnace 13; an inlet conduit 15 for raw oil shale ore with a ilow control device 17 located in the conduit; a flow control device 19 at the bottom of the retorting furnace 13; and a ow conduit 21 that carries away the retorted shale ore.

Recycle gas is introduced into the retorting furnace 13 through conduit 23 and also through conduit 25 at a level slightly below the mid-region of the furnace 13. The vaporous kerogen is removed through a conduit 27 at the top of the retort furnace 13. A conventional exhaust fan 29 withdraws the vaporous kerogen through a precipitator 31 and urges the gases through a cooler-condenserdecanter 33. An external heater 35 is frequently provided in the conduit 25, about where shown in FIG. 1, to heat the recycle gas prior to entry into the retorting furnace 13.

In contrast to the prior art apparatus 11, FIG. 2 illustrates a rst apparatus 37 in accordance with the invention, that is suitable for carrying into practice the method of the invention. Such apparatus 37 includes: an upper portion 39, and an interconnecting lower portion 41.

The upper portion 39 is similar to the retorting furnace shown and described in copending application Ser. No. 670,275, filed Sept. 25, 1967 and assigned to the assignee of this invention. Briefly, such retorting furnace portion 39 includes a cylindrical outer shell 43 which is lined with suitable refractory material (not shown). The top of the cylindrical shell 43 is connected to the larger end of a frusto-conical member 45 that connects, at its top, to a bell housing 47 wherein are located upper 49 and lower 51 bell structures. Within the frusto-conical member 45 there are a plurality of concentric, vertically-separated, louver-rings 53 that are suitably iixed to the frusto-conical member 45, and also to the cylindrical shell 43.

A plurality of horizontal gas off-takes 55 are located within the cylindrical shell 43, and they are connected to a product header 57 surrounding the shell 43. Below the gas off-takes 55, there is a gas distributor assembly 59 that conducts recycle gas into the upper furnace portion 39 to provide a source of heat and a means to sweep upwardly gas and released kerogen products. In some applications, a mixture of air and recycle gas may be burned at the distributor 59 to retort the oil shale ore.

In some applications, an additional distributor 59a may be located in the position where shown in FIG. 2 for a purpose described hereinafter.

The lower end of the upper furnace portion 39 is closed by a plurality of frustoconical members 61 (it may be closed also by a single frusto-conical member if preferred) at the bottom of which there is an ore crusher 63, preferably of the twin-roller type.

The lower portion 41 of the apparatus 37 includes a generally cylindrical shell 65 which is attached to the larger lower ends of a plurality of frusto-conical member 67 (or to a single frusto-conical member if preferred) which also connect to the discharge ends of the aforementioned crushers 63. The lower end of the cylindrical shell 65 is connected to the larger ends of a plurality of other frusto-conical members 69 (the shell 65, too, may be connected to a single large frusto-conical member) which are closed at their respective lower ends by suitable fiow control devices 71, such as rotary vane feeders.

Within the cylindrical shell 65 is a plurality of gas offtakes 73 which are connected, external the shell 65, to a surrounding header 75.

Beneath the off-takes 73, there is a gas distributor arrangement 77, that includes a header 79 surrounding the cylindrical shell 65; such gaseous distributor header 79 being in fluid communication with a source of gas, such as recycle gas, flowing in conduit 81.

Beneath the gaseous distributor arrangement 77, and just above the top of the frusto-conical member 69, there is a conventional movable grate 83, which may be of the type described in the aforementioned copending application, Ser. No. 670,275.

Adjacent the lower furnace portion 41, or in any convenient other location, there is a conventional cyclone separator 85, which is in communication with the off-takes 73 by means of conduit 87, and with the distributor 59 by means of conduit 89.

A conduit 91 connects the gas distributor 59 with a source of recycle gas, and a conduit 93 conducts the product gas and oil away from the product header 57.

The bottom of the cyclone separator 85 is provided with a flow control device 95, such as a rotary vane feeder, so that ore fines, deposited in the separator 85, discharge through conduit 97 to a suitable other depository.

In operation, raw oil shale ore is fed into an opening in the top of the bell housing 47, as indicated by the arrow A. The feed consists of oil shale ore that has been broken and screened to approximately 1A inch4 inch size particles. The use of large size particles in the upper portion 39 of the retorting furnace offers the benefit of high throughput at low pressure drop.

The shale ore particles pass through a preheating zone and a retorting zone, as they descend the upper portion 39 of the furnace.

In applications where there are two distributors such as 59, 59a, in the upper portion 39, the additional distributor 59a would be fluidly connected to conduit 89 by another conduit 90 in which there is a valve 90a, as shown in FIG. 2.

The shale ore particles then pass through the double roller Crushers 63 wherein the organic rich central core of each particle is comminuted. Crushing of the shale particles, while hot, releases additional, secondary-recovery, product gas and oil which is removed from the lower portion 65 by a sweep upward of cool recycle gas introduced into the lower portion through conduit 81, header 79, and the distributor 77. This sweep upward of cool recycle gas also serves to cool the countercurrent, descending flow of comminuted shale ore.

The recycle gas and the additional product gas and oil flow from the lower portion 41 through the off-take 73 and header 75, and pass into the separator wherein ore fines are separated out.

The secondary-recovery gas and oil, carrying the additional oil and gas products released from the comminuted particles in the lower portion 41 recovery zone, may be introduced into the bottom of the upper portion 39 through distributor 59, along with either heated recycle gas, or with a mixture of recycle gas and air. In the latter case, the mixture of recycle gas and air may be burned at the fuel distributor 59. In this instance, valves a and 99 would be closed and valve 101 would be open.

In another application, recycle gas may be heated by an externally fired heater, such as the heater 35 shown in FIG. 1, and only such heated recycle gas will flow into the gas distributor 59. In this instance, the heated recycle gas is not burned at the distributor 59; valve 101 is closed and valve 99 is open. Therefore, the secondary recovery gas mixes with the primary product gas and oil owing in conduit 93.

In the event there are two distributors 59 and 59a in the upper portion 39, then the secondary recovery gas and oil may be introduced at distributor 59a and either heated recycle gas, or a mixture of recycle gas and air may be introduced through distributor 59. In the latter case, the mixture of air and recycle gas may be burned at the distributor S9. In this instance, valves 99 and 101 would be closed and valve 90a would be open.

The spent shale ore is discharged from the bottom of the furnace lower portion 41 through flow control device 71 into conduits 103 which conduct the spent shale ore to a suitable depository.

FIG. 3 illustrates a modified retorting furnace 37a that is similar to the apparatus 37 of FIG. 2, except that an additional gas distributor arrangement is incorporated into the lower portion 65a of the retorting furnace 37a. By means of such gas distributor 105, heated recycle gas is introduced into the lower portion 65a through conduit 107 to provide additional heat, if required, to assist in the release of the kerogen from the comminuted oil shale ore. An alternate heating method would be to introduce air along with the recycle gas for internal combustion.

FIG. 4 illustrates another modified retorting furnace 37b that is similar to the apparatus 37 of FIG. 2, except that a pair of ow control devices 109, 111, are provided above and below each Crusher mechanism 63. Such control devices 109, 111 may be rotary vane feeders, or other suitable apparatus if preferred. Further, a movable grate mechanism 113 is installed in the bottom of the upper retort portion 3917; the lower portion 6Sb of the retorting furnace 37b being substantially the same as the lower portion 65 of the retorting furnace 37 described hereinbefore.

From the foregoing description, those skilled in the art will recognize the novel features and advantages of the present invention, among which are:

A considerable amount of additional energy in the form 0f kerogen is recovered by the secondary recovery apparatus and the method of the invention, which additional kerogen is not recoverable by practicing processes known in the prior art;

Such recovery of kerogen may be as much as 10% of the amount of kerogen recovered in a first stage apparatus operated in accordance with methods known in the prior art;

Such secondary recovery kerogen may be mixed with air and burned to provide additional heat to assist in the release of more kerogen from the oil shale ore in a first stage apparatus.

Although the invention has been described herein with a certain degree of particularity, it is understood that the present disclosure has been made only as an example and that the scope of the invention is dened by what is hereinafter claimed.

What is claimed is:

1. An apparatus having two stages for retorting oil shale ore comprising:

(a) an upper first stage portion through which raw oil shale ore particles flow;

(b) a product off-take conduit to remove gas and kerogen from the upper shaft furnace portion;

(c) a gas distributor in said upper furnace portion to introduce heated gas thereinto for retorting said shale ore particles;

(d) means connected to the oil shale ore discharge end of said first stage portion for comminuting said shale ore particles after they have been retorted and have flowed through said furnace;

(e) a lower second stage portion including a receptacle connected to said comminuting means for receiving said comminuted particles;

(f) means for flowing a gaseous fluid upwardly through said comminuted particles to remove product gaseous fluids liberated from each particle after being cornminuted;

(g) means for removing said product gaseous fluids from said receptacle; and

(h) means for discharging said comminuated particles from said receptacle.

2. The apparatus of claim 1 wherein said receptacle inludes:

(a) grate means to control the flow of said comminuted particles through said receptacle.

3. The invention of claim 1 including:

(a) means for separating particulate matter from the gaseous fluids removed from said receptacle;

(b) conduit means connecting said separating means with both said product off-take conduit and said gas distributor; and

(c) valve means in said conduit for selectively passing said separated gaseous fluids into said off-take conduit or said gas distributor.

4. An apparatus having two stages for retorting oil shale ore comprising:

(a) an upper first stage portion through which raw oil shale ore particles flow;

(b) a product off-take conduit to remove gas and kerogen from the upper shaft furnace portion;

(c) a distributor in said upper furnace portion to introduce a combustible gas thereinto which burns at said distributor, the heat generated retorting said shale ore particles;

(d) means connected to the oil shale ore discharge end of said first stage portion for comminuating said shale ore particles after they have been retorted and have flowed through said furnace;

(e) a lower second stage portion including a receptacle connected to said comminuting means for receiving said comminuted particles;

(f) means for flowing a heated gaseous uid upwardly through said comminuted particles in said receptacle to sweep upwardly gas and released kerogen products;

(g) means for removing said gas and released kerogen products from said receptacle; and

(h) means for discharging said comminuted particles from said receptacle.

5. The invention of claim 1 including:

(a) means for controlling the flow of shale ore particles from said vertical shaft furnace into said comminuting means.

6. In the method for retorting raw kerogen-bearing shale oil ore, including the steps of feeding particulate shale oil ore into a retorting shaft furnace, retorting the oil shale ore, and removing product gases and oil from said furnace, the improvement comprising the steps:

(a) comminuting said shale ore particles upon leaving said retorting shaft furnace;

(b) collecting the comminuted particles in a receptacle;

(c) cooling said comminuted particles by passing a gaseous uid through the comminuted particles in said receptacle whereby the product gases and oil released from said particles as a result of comminution are entrained with said gaseous fluid; and

(d) removing the gaseous fluid and product gases and oil from said receptacle.

7. The method of claim 6 including the steps:

(a) regulating the ow of shale ore particles from said furnace before said particles are comminuted; and (b) regulating the flow of said comminuted particles into said receptacle.

8. The method of claim 6 including the step:

(a) retorting the comminuted particles in said receptacle.

9. The method of claim 6 including the steps:

(a) flowing the gaseous fluid, having entrained therewith product gases and oil, into said furnace;

(b) mixing said gaseous fluid with other combustible gaseous fluid in said furnace; and

(c) burning said mixed gases in said furnace.

10. The method of claim 6 including the steps:

(a) heating a gaseous fluid and passing such uid into said furnace to aid in the recovery of the product oil and gases from said particulate shale oil ore; and

(b) mixing the gaseous uid and the product gases and oil removed from said receptacle with the product gases and oil removed from said furnace.

U.S. Cl. X.R. 

